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EPUBCheck · Package document (OPF)

OPF-088

Updated:

EPUBCheck OPF-088 is a usage message: “Unrecognized epub:type value "…".” An epub:type value is not in the EPUB structural semantics vocabulary, so reading apps will ignore it.

The official message

Unrecognized epub:type value "%1$s".

Default severity
Usage. Informative only and hidden by default: it appears when EPUBCheck runs with -u (--usage). It does not make the EPUB invalid.
EPUBCheck version
5.4.0

%1$s, %2$s… are filled in with the file, value or element EPUBCheck found.

Typical causes

  • A misspelling such as "footnotes" on a single note, or a value invented for styling.

How to fix it

  • Use a value from the vocabulary, or give a custom value a declared prefix. Use class for styling.

Terms used here

Other OPF messages

  • OPF-086 Property "…" is deprecated. Consider using … instead.
  • OPF-086b epub:type value "…" is deprecated. Consider using … instead.
  • OPF-090 It is encouraged to use MIME media type "…" instead of "…".
  • OPF-085 "dc:identifier" value "…" is marked as a UUID, but is an invalid UUID.
  • OPF-091 The item href URL must not have a fragment identifier.
  • OPF-092 Language tag "…" is not well-formed: …

Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EPUBLab.

FAQ

What does EPUBCheck OPF-088 mean?

EPUBCheck OPF-088 is a usage message: “Unrecognized epub:type value "…".” An epub:type value is not in the EPUB structural semantics vocabulary, so reading apps will ignore it.

Is OPF-088 an error?

OPF-088 is reported as usage by default. Informative only and hidden by default: it appears when EPUBCheck runs with -u (--usage). It does not make the EPUB invalid.